When an exposed silver halide photographic material is subjected to color development, a developing agent such as aromatic primary amine which has been oxidized by silver halide reacts with a dye-forming coupler to form a color image. This color development is normally accomplished by the subtractive color reproduction process. In this process, the reproduction of blue, green, and red is effected by forming color images of yellow, magenta, and cyan, which are complementary to blue, green, and cyan, respectively.
As cyan-dye-forming couplers, phenolic and naphtholic types have been used. However, the stability of color image obtained from such conventional phenolic and naphtholic couplers leaves to be desired. For example, a color image obtained from a 2-acylaminophenol cyan-dye-forming coupler (also referred to herein more simply as a "cyan coupler") as described in U.S. Pat. Nos. 2,367,531, 2,369,929, 2,423,730 and 2,801,171 is generally poor in fastness to heat A color image obtained from a 2,5-diacylaminophenol cyan coupler as described in U.S. Pat. Nos. 2,772,162 and 2,895,826 is generally poor in fastness to light. 1-Hydroxy-2-naphthamide cyan coupler generally leaves much to be desired in fastness both to heat (moist heat) and light.
In recent years, nitrogen-containing heterocyclic condensed cyan couplers as represented by formula (C-I) of the present invention have been found to eliminate the above-mentioned shortcomings of cyan-dye-forming couplers. These couplers are excellent in fastness to heat and light as compared to the prior art couplers.
However, it was found from the inventors' extensive studies that these nitrogen-containing heterocyclic condensed cyan couplers leave much to be desired in the stability of color images formed in a color light-sensitive material as compared to yellow or magenta couplers.
Such a deterioration of image quality is a serious defect in a recording material.
Heretofore, studies have been made to develop various dye stabilizers for magenta couplers t inhibit such a deterioration of image quality.
Examples of such dye stabilizers for magenta couplers include hydroquinones, 6-hydroxychromans, 5-hydroxycoumarans, spirochromans, spiroindans, p-alkoxyphenols, hindered phenols such as bisphenols, gallic acid derivatives, methylenedioxybenzenes, aminophenols, hindered amines, and ether or ester derivatives obtained by silylating, acylating or alkylating phenolic hydroxyl groups thereof. Metal complexes are known as such dye stabilizers.
However, these dye stabilizers are not always sufficiently effective for the stability of cyan images even though these are effective for magenta images. Some dye stabilizers worsen the preservative stability.
On the other hand, it has been known that an ultraviolet absorber or a combination of certain types of high boiling organic solvents (Japanese Patent Publication Nos. 15380/82 and 45014/83, and Japanese Patent Application (OPI) No. 99432/79 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application")), certain phenol compounds (Japanese Patent Application (OPI) Nos. 48535/79, 3432/84, 124340/84, 222853/85 and 86750/86), hindered amine compounds (U.S. Pat. No. 4,268,593, and Japanese Patent Application (OPI) Nos. 114036/83, 124340/84 and 222853/85), ester compounds (Japanese Patent Application (OPI) No. 3433/84), and ether compounds (Japanese Patent Application (OPI) Nos. 77527/78 and 11453/71) is used for the purpose of improving the stability of cyan images.
It is true that these compounds are effective for resisting the deterioration or discoloration of dye images. However, such an effect is sometimes small. Some compounds are effective for inhibition of discoloration, but can deteriorate color hue or cause fog, poor dispersion, or crystallization. In general, therefore, these compounds do not serve well as photographic dye stabilizers for excellent effects.